RESUMO
The cellulose nanocrystals (CNC) has attracted widespread attention in reinforced materials. However, the application of CNC in electrospinning has been limited due to its self-polymerization. Herein, a cobweb-like nanofibrous membrane was fabricated by electrospinning the polyacrylonitrile (PAN) and sulfydryl-functionalized CNC (SC). The SC content could reach to 48 wt% after the thiolation modification. The membrane with ultrafine fibers and interlaced nets possessed outstanding porosity (91.7%) and underwater superoleophobicity. An ultrahigh permeation flux of 1244 L·m-2·h-1 with a separation efficiency of >99.9% was achieved driven by gravity. The mechanical properties also enhanced significantly with the increase of SC. When the addition amount of SC was 48 wt%, the maximum tensile stress was 2.9 MPa, which was 3.4 times than that of the PAN membrane. The antifouling performance and chemical stability endowed the SC(48)/PAN membrane with intriguing reusability, thus making it exhibit enormous potential in oil/water separation.
RESUMO
Despite recent advances in the stimuli-responsive composites for oil storage and smart lubrication, achieving the high oil storage and recyclable smart-lubrication remains a challenge. Herein, a novel cobweb-like structural system consisting of oil warehouse and transportation system was designed and prepared and it shows high capacity of oil storage and recyclable smart-lubrication. Hollow SiO2 microspheres grated of KH550 and porous polyimide (PPI) were used as oil warehouse and pipeline, respectively, to build the smart system. Because of the novel structure, the composites can keep both high oil-content and oil-retention. Applying stimuli on materials resulted in lubricants releasing on the contact surface which can reduce the friction and wear during sliding. However, removing stimuli, the capillary force induced the sucking back of lubricant into the interior of composites through interconnected small pores of PPI. On the basis of high oil storage and stimuli-responsive performance, the composites can be used for recyclable smart-lubrication. The composites showed remarkable lubricating properties (coefficient of friction 0.056 and Ws 3.55 × 10-7 mm3 N-1 m-1) when the content of KHSM (hollow silica microspheres grated of KH550 (3-Aminopropyltriethoxysilane)) was 1.5 wt % by subjecting it to macroscopic pin-on-disc friction tests. Therefore, cobweb-like structural composites with oil warehouse and transportation system hold the promise for formulating of high oil storage and recyclable smart-lubrication.